(6.0 x 10^5) x (3.0 x 10^4) = (6 x 3) x 10^(5 + 4) = 18 x 10^9 = 1.8 x 10^10
It's hard to type and hard to read the "inverse tangent" function, as you've seen (above).
So, use "arctan x" instead.
Then the problem becomes: "differentiate cos (arctan x)."
You must apply first the rule for differentiating the cosine function, and next apply the rule for differentiating the arctan function:
(d/dx) cos (arctan x) = - sin (arctan x) * [1/(1+x^2)]
Point H shows 45 because 6.7 multiplied by each other equals 45 and 6.7 on the line is point H
